I went down a fun rabbit hole recently. It started with the innocent question "How much iron is in the sun?" fun because the answer ranges from fractional percentages to the sun is a stellar remnant and most of it is iron.
Here is one of the more out there theories I found.
The fractional percent crowd bases their theory on the observed spectrum of the sun. the large iron core side bases their theory on the observed distribution of iron in the inner solar system.
It is interesting because too much iron and there would be no fusion, but think of the iron cores in the planets, the sun coalesced from the same dust, there has to be a large amount in there.
Here is one of the more out there theories I found.
https://arxiv.org/ftp/astro-ph/papers/0410/0410569.pdf
The fractional percent crowd bases their theory on the observed spectrum of the sun. the large iron core side bases their theory on the observed distribution of iron in the inner solar system.
It is interesting because too much iron and there would be no fusion, but think of the iron cores in the planets, the sun coalesced from the same dust, there has to be a large amount in there.